A hybrid cold atom/classical accelerometer was considered by [1]}, where the atom interferometer signal phase is compensated by using the signal of a classical accelerometer. A similar idea is presented in [2]}, where a hybrid system combines the outputs of quantum and classical accelerometers in an optimization framework. An extended Kalman filter is used in the loop to estimate the bias and drift of a classical sensor as well as the phase of a quantum sensor. This results in a bandwidth of 400Hz and a stability of 10ng after 11 hours of integration by the hybrid sensor. Although the accuracy of the quantum accelerometer was in the range of (0100g, simultaneously estimating the quantum sensor phase and classical sensor bias is nontrivial. Both the above two approaches are related to our work in the sense of estimating the phase of a quantum accelerometer but differ in implementation and how the classical sensor bias is removed. More recent work by [3]} investigates the possibility of using the measurement of a cold atom interferometer sensor in Mach-Zehnder configuration in a navigation solution. They combine the cold atom sensor measurement with classical inertial sensors via a filter solution, observing an improved navigation performance when the underlying acceleration is small.
